Summary/Abstract This is a request for an extension of the Biostatistics and Epidemiology in AIDS Training Program at the Harvard T. H. Chan School of Public Health (HSPH). The program prepares pre-doctoral and postdoctoral fellows in the application of biostatistics and epidemiology to HIV research. The program is an active collaboration between the Departments of Biostatistics and Epidemiology. Trainees receive high-quality instruction in basic biostatistical theory and methods, such as probability, statistical inference, computing and data analysis. The program also provides training in specialized topics of particular relevance for HIV/AIDS applications, such as survival, longitudinal and multivariate data analysis, causal inference and statistical genetics. Options are available for training in computational biology/bioinformatics and health data science (?big data?) as these are increasingly important areas for HIV research. Training is also provided through substantive course work in HIV-related topics, most commonly in HIV epidemiology, topics in immunology, virology and infectious diseases, or health policy pertaining to the HIV pandemic. Trainees participate in a regular ?HIV Working Group? seminar series where faculty, students, and fellows present their HIV-related research, as well as in seminar discussions about developing clinical trials and observational studies in HIV research organized by the HSPH Center for Biostatistics in AIDS Research. An important focus of training is the opportunity to work with faculty on HIV-related biostatistical and epidemiological methods research including, for pre-doctoral students, the development of a doctoral research thesis. Trainees participate in Harvard's program on scientific integrity in the conduct of research, formal coursework on grant writing and methods to ensure reproducible science, training in effective biostatistical consulting, and workshops on effective writing, public speaking, and career development. Since its inception in 1988, this training program has emphasized strong links to HIV/AIDS research, particularly those through the HSPH AIDS Initiative including the Botswana Harvard Partnership, and through the large statistical centers at HSPH which work with international HIV clinical trials research networks and with the Pediatric HIV/AIDS Cohort Study. The Program has a particular focus on the recruitment of students from underrepresented minority groups and their successful completion of training. The focus on interdisciplinary training at the Harvard T. H. Chan School of Public Health, as well as its talented and diverse student body and faculty, makes it ideally suited for a training program in biostatistics and epidemiology applied to HIV research.